//#include<stdio.h>
//
//int my_strlen(char* arr) {
//	char* ret = arr;
//	while (*arr != '\0') {
//		arr++;
//	}
//	return arr - ret;
//}
//int main()
//{
//	char arr[20] = "ABCDEF";
//	int c=my_strlen(arr);
//	printf("%d", c);
//	return 0;
//}
//#include<stdio.h>
//
//char* my_strcpy(char* arr2,char* arr) {
//	char* ret = arr2;
//	while (*arr != '\0') {
//		*arr2 = *arr;
//		arr2++;
//		arr++;
//	}
//	return ret;
//}
//int main()
//{
//	char arr[20] = "ABCDEF";
//	char arr2[20] = {0};
//	char* c = my_strcpy(arr2,arr);
//	printf("%s", arr2);
//	return 0;
//}
#include<stdio.h>

char* my_strcat(char* arr2, char* arr) {
	char* ret = arr2;
	while (*arr2 != '\0') {
		arr2++;
	}
	while (*arr != '\0') {
		*arr2 = *arr;
		arr2++;
		arr++;
	}
	return ret;
}
int main()
{
	char arr[20] = "wucheng";
	char arr2[20] = "nihao ";
	char* c = my_strcat(arr2, arr);
	printf("%s", c);
	return 0;
}

